Process of forming curved flanged bars



Apu'. R7, E923. 1,452,225 R. S. SMITH PROCESS OF' FORMING CURVED FLANGED BAS Filed March 3l, 1920 mL v --1U ",m

OFI-SETTING PREs Del,

atented Apr. 1.7, 1923.

gnarran srA-TEs PATENT. OFFICE.

YIBEIUBENl STANLEY SMITH, OF MILWAUKEE, WISCONSIN, ASSIGNOR TO A. O. SMITH CORPORATION, OF MILWAUKEE, WISCONSIN, A CORPORATION OF NEW YORK.

` Pnocnss or FORMING CURVED FLANGED BARS.

Application mea March s1, 1920. serial 110.370,136.

To all whom tv may concern.'

Be it known that I, REUBEN STANLEY SMITH, a citizen of the United States, residing inthe c ity of Milwaukee, county of Milwaukee, and'State of Wisconsin, have invented certain new and useful Improvelments in Processes of Formingy Curved Flanged Bars (Case No. 149); and I do herebyy declare the following to be a full, clear, and exact description thereof, such as will enable persons skilled in the art to which the invention relates to reduce the -invention to practice, reference being had to the drawing hereto attached for disclosure as to certain details constituting the .dominant features of my invention.

My invention relates to improvementsin processes for shaping sheet metal blanks, particular reference being made to that class of structures in which the side margins -of a curved sheet metal blank are bent perpendicularly to the central portion or web of the blank to form a channel bar, for example, such as constitutes'one of the side vbars or cross bars of automobile or other vehicle frames.

My 'invention is embodied in the process of imparting a succession of edgewise bends to a single rectangular metal plate, so that by distorting the parallel edge lines of such glate, a plate of varyingoutline will e produced and of such area as to permit a curved blank of predetermined contour to be punched therefrom, it being understood that the maximum width of such curved blank between the projected edge lines thereof greatly exceeds the Width of the plate from which the blank is to be punched.

M V invention resides also in the process of distorting the cross lsection of the,A blank at points so as to increase the thickness thereof, and thus constitute reinforcements in certain areas, and by this procedure .I

. obviate the vnecessity for separately reinforcing the side bar at the points which are subjected to breaking strains.

Heretofore the general practice has been to punch lthe curved side and cross bar blanks from rectangular plates or sheets of of scrap when compared with the scrap l created by the older processes of punching the curved blank from a rectangular plate of ample Width. In the.later process in which the curved blank ispunched from a metal plate which has been bent edgewisc or in" the direction of its width, the side lines of the curved plate are made to conform as closely as p ossible to the contour lines of the curved blank to be punched therefrom. The skeleton of the curved plate created by punching out the curved blank, is so attenuated that waste is practically eliminated,.and the small amount of material remaining in the skeleton has no value other than that of scrap.

W'hile it has been entirely practicable to impart a singleA edgewise bend or curve to a plural number of plates in one operation, it has not been, prior to my invention, practicable to impart in one operation more than a, single` bend to such plural number of plates. Nor has it been possible heretofore to bend a single plate edgewise.

The edgewise bending of a plural number A of plates in one operation has been achieved by the use of a die member having a thickness equal to the aggregate thickness of the plural number of plates, usuallyA four or five, operated upon at one time. The die so used, by reason of its thickness, possesses a degree of stiffness and rigidity sufficient to .cause it to stand up under the great pressure imposed upon it in the bending operation. But the insurmountable obstacle encountered in attempting to bend a single plate edgewise, resides in the inability to construct the thin blade of the die, the thickness of which approximates the gaugeof the plate to be bent, so as to possess sufficient strength to enable' such die to withstand the enormous compressive strain exerted in the bending operation.

But my improved process enables me to impart an edgewise bend to a single plate, and this result is brought about by the use of offsetting dies of' improved formation, as Will be described hereinafter. In the old practice of offsetting a plural numberof platesedgewise, it has been possible to 1mpart but a single bend to such plates in one operation. sired in the metal plates it was necessary to subject the plates to further treatment by the offsetting dies in further similar operations.

My improved process contemplates the bending of a single metal plate and impart-l ing thereto in a single operation of the offsetting press, all of the curves, either single or compound, which it may be desired to produce in the curved plate to enable any desired configuration of curved blank to be punched therefrom.

An offsetting press which may be used to carry out the process involving my present invention is disclosed in Patent No. 1,340,138, granted May 11, 1920, on an application filed by Henry Miller, March l30, 1918, Serial #225,791, and also, by the improved offsetting press disclosed in the application filed by R. Stanley Smith, the present inventor, together with Henry Miller and Frederick Orton, March 22, 1920, Serial #367 ,7 99. The offsetting presses disclosed in the aforesaid patent and application areydesigned to operate upon a single metal plate, so as to produce therein by one operation of the press al1 of the desired curves, and the plate will be so contoured asl to enable the particular curved blank to be punched therefrom.

An offsetting press operating in the manner just referred to, Will constitute an element of the assemblage of machines disclosed in Patent No. 1,397,020, granted November 15, 1921, on my application,v Serial #212,934, filed January 21, 1918, such assemblage including machines, which by their related, connected and successive operations, punch from metal plates the side and cross bar and other blanks used in constructing an automobile or other vehicle frame, shape such blanks according to the particular requirements appertaining to each of them, perform the necessary milling operations thereon, assemble the several constituent frame parts, and secure all of such parts in their respective positions, so that in a continuous operation of mechanical devices a completed automobile or other velucle frame is automatcally produced. The assemblage disclosed in my said PatentV No.

1When other curves were de-A releases 1,397 ,020 is timed to operate upon a schedule providing 4:for the production of a given number of automobile frames per minute, and each machine element of the assemblage performs its operation in a predetermined fraction of the time-cycle of the operation or" the assemblage. Ylhe requirements imposed by the described co-ordinated operation of the machines of the said assemblage have necessitated the movement of the metal plates in a continuous and uninterrupted stream through the offsetting elements'ot the assemblage in single file order, and this vention, and the offsetting presses rwhich have been designed to fulfill the purposes thereof. But in actual practice, my present invention as Well as the offsetting press, need not be limited to operation upon a single plate, inasmuch as a plural number of rectangular plates may be fed to the osetting press for bending in a single operation of the press, if such plates are not to be distorted otherwise than in the direction of' their Width.

As above indicated, it has not been possible heretofore to offset edgewise a single metal plate of considerable Width, by reason of the fact that the offsetting die employed to impart an edgevfise bending pressure-to the metal plate could not have a thickness greater than that of the metal plate. Consequently, in all previous attempts the thin bladeof the offsetting die would buckle under the pressure imposed, and'so fail to effect the offsetting operation. The difficulty previously encountered, however, has been overcome by the production of dies of peculiar form, and the pressure of which is directed angularly against'the edgesand sides of the metal plate, as disclosed in the said Patent No. 1,340,138, and Serial No. 367,799, the offsetting press being equipped with a pair of offsetting dies, each of which is provided with a curved portion designed to engage one of the edges of the plate and of a width approximating the thickness ofA the plate to be offset. Such dies are provided also With facing portions designed to bear on the sides of the metal plate and hold such plate against buckling as the dies are moved over each other to bring the edge engaging por- Yrequirement has been met by the present intions into contact with the plate and bend the latter as such edge engaging portions approach each other.

The foregoing statement of my invention pertains to the edgewise bending of rectangular plates of metal, in which the plane or side surfaces of the plate are prevented from distortion by reason of the angular pressure of the offsetting dies, the edge engaging portions of which are suitably contoured to bend the metal plate in the direction of its Width and in the plane of the stroke of the dies.

`But in some types of automobile frame side act only to produce a lateral displacement of the longitudinal dimensions of the metal plate, such curved offsetting portions of the vdie moving in lines which maintain their parallelism, so that such offsetting portions of the dies are substantially equidistant at all times in the offsetting operation. Under such conditions the metal of the plate' can flow only from the edge "of one offsetting die to thecorresponding edge of the other. But when it is desired lto thicken the plate at certain points for the purpose of constituting the reinforcement described, the offsettin.'` dies are formed and assembledfso thatv at t e points where reinforcement is desired, the dies will more closely `approach each other and thus narrow the plate at such A points. To permit the metal of the plate at such times to fiow. in a direction which is transverse to the plane in which the plate lies, and so achieve the thickening desired,

' I cnt away the side surfaces of the offsetting dies in a slight degree, so that when the angular pressure of the offsetting dies is appl'ied, the metal ofthe plate will also flow into the cut away portions of the dies, by

reason of the room for expansion thus provided, and in this manner the metal plate with thickened portions constituting the desired reinforcements is produced.

In the accompanying dra-wing,

Figure 1 is a`plan view-of a rectangular sheet metal plate shiJ ving the excess of width heretofore required to enable a curved blank of irregular outline to be punched therefrom, the view also showing in dotted lines the outline of such curved blank, and the skeleton of the plate bordering on the curvedl blank indicating the amount or extent. of the waste of material involved.

Fig. 2 is a plan View of a much narrower rectangular plate which is designed by my process to be bent in the direction of its width. so as to provide such plate with an irregular area and enable the curved blank indicated in Fig.- 1 to be punched therefrom.

Fig. 3 is an edge view of. the metal plate showing its normal construction.

Fig. 4 is a plan View of the metal plate shown in Fig. 2, and showing the configuration of the said plate produced by the edgewise bending` operation referred to, and

having indicated thereon by dotted'lines the outline of the curved blank which may be punched therefrom,with the practical reduction of the waste material t-.o a minimum.

Fig. 5A is a plan View of the curved blank punched from the curved plate shown in Fig."4.

Fig. 6 is an edge view of the blank shown in Fig. 5, but showing such blank as reinforced at its narrower or end portions, such vreinforcement following the "thickening of the blank at such operation.

Fig. 7 is a perspective view of a curved flanged side bar for the frame of an automobile or other vehicle, and showing such side bar as reinforced at itsy narrower or end portions in the bending portions.

Figs. 89 and 10 respectively are views on the lines 8 8, 949, 1O-V1O, Fig. 7, indicating b y comparison the manner in which the reinforcement described is created in the fianged side bar.

Fig. 11 is a rectangular plate from which a blank for a curved cross bar of an automobile frame may be p-roduced.

Figi 12 is a planrview ofthe plate shown in Fig. 11 after .having been subjected to the edgewise bending operation.

Fig. 13 is a view in elevation of a curved flanged cross bar produced from the curved blank shown in Fig. 12 and reinforced through its central section. y

Figs.'14 and 15 are sectional views on the lines 14-14 and 15-15, respectively` Fig. 13, to show the reinforcementin the central portion of the cross bar.

Fig. 16 is designed to illustrate in a conventional manner the arrangement of the offsetting dies with a metal plate between them, which plate will be bent edgewise to conform the edge lines thereof to the curvature of the dies, when the latter are caused to approach each other in the offsetting operation.

Fig. 17 isan end view, from the right, Fig. 16, showing the slight clearance provided inthe dies to permit the-expansion or vthickening of the plate when the compreive ing been subjected to the offsetting ope-ration, according to my improved process.

Referring to Figure 1 of the drawing, a rectangular plate of a width sufficient to enable a curved side bar blank of predetermined contour to be punched therefrom, is indicated by the numeral 10. This 'figure has indicated thereon in dotted lines a curved flat blank 11, and by comparison of the respective outlines of the plate and the blank,4 it will be seen that the marginal or skeleton portion of the plate lying beyond the outlines of the blank embodies an area greatly in excess of that which is required ir the formation ofthe blank. The excess of area residing in the marginal skeleton involves an appreciable amount of Waste of expensive material, and the creation of such waste, duc to quantity production. largely exceeds the legitimate manufacturing uses thereof, s-o that the Waste must be disposed f as scrap,it having no other valuation.

Fig. 2 shows a rectangulary plate 12 having a width which is approximately one third less4 than the Width of the plate 10, and yet which plate 12 may be so transformed in the practice of my invention, that the facial extent of such plate will be changed so that the blank 11 maybe punched therefrom, with a 'clear saving of at least a third of the material formerly required in producing the identical blank. The rectangular plate 12, after its transformation by edgevvise bending, is indicated at 13 in Fig. 4, in which the dotted outlines of the blank 11 to be punched therefrom indicate by comparison the saving of material effected by the practice of my invention. Viewing Fig. 4, it Will be seen that the skeleton of the plate lying outside of the lines indicating the blank, is so reduced that the Waste resulting from the practice of the older processes is practically eliminated, and that the material constituting the said skeleton is of such small dimensions in all of its parts that it has no value for other manufacturing purposes. As a consequence, the Waste material resulting from the practice of my invention is void of any value except that which merely attached to it as scrap.

As outlined in the statement of the invention at the commencement of this specification, it hasbeen possible heretofore to impart a singlecurve or edgewise bend to a plural number of plates. But it has not been feasible to impart more than a single curve or edgewise bend 4to a plural number of plates in one operation, and such pluralv number of plates have of necessity been subjected to further bending operations when it was desired to produce additional curves or bends therein. Certain mechanical difficulties, hereinbefore referred to, vhave served to defeat all previous attempts to bend a single plate in the` direction of its width. The difficulties referred to reside in the fact that it is not possible to construct a thin, flat offsetting die with strength suficient to withstand the pressure applied to the edge of the plate in the bending operation, it being necessary that the vplate to be bent be sustained by lateral guides to prevent buckling of the plate, and the thin osetting die being required to move into the spa-ce provided by the separation of the guides, and following the Widthwise movement of the metal of the plate under the pressure exerted upon the offsetting die.

In my application filed September 12, 1921, Serial #qt-500,019, I have disclosed the constructionof the special dies which are employed to carry out my present invention, and will refer but briefly to such dies in the present case, such brief reference being sufficient for an understanding of the manner in which my present invention is put into practice. The o'setting dies which are used in carrying out my improved process ol bending metal plates in theA direction of their Width, are conventionally shown in Figs. 16, 17and 18. The lower die member 14 may here be described as constituted of a plate haying a flat face 15 upon which the metal plate 12 to be subjected to the bending operation is placed. At one edge the die member 14 is provided with an angularly formed offsetting die 16, which will be curved throughout its length to produce the desired contour inthe plate from Which the blank is to be punched. The edge engaging portion 16 of the die will be commensurate with the gauge of the. plate which it is desired to offset.

The companion offsetting die member 17, corresponding in construction to the offsetting die member 14 first described, is imposed upon the die member 14, so that the flat faces 15 and 18 of the said dies bea-r upon the opposite sides of the plate 12, the offsetting edges 16 and 19 of the dies being at such times in line With the edges of the plate to be bent. The die member 14 is .maintained in a relatively fixed position, but

an angular thrust is applied to the die mem ber 17, as described in Patent No. 1,340,168, and. application Serial No. 367,799, with the result that the flat faces of the dies engage the sides of the metal plate 12 with a clamping pressure, which latter is sufficient to .prevent the plate from buckling when the bending pressure is applied to the edges thereof, in the further movement of the die member 17, under the angular pressure described. The points and depressions of the correspondingly contoured edges 16 and 19 of the offsetting dies are opposite each other in the respective dies, so that the offsetting pressure of the dies is applied to the opposite edges of the plate at points which are staggered with relation to each other. The points on the offsetting edges of the opposite dies are indicated at Ua, Fig. 16. The result of this arrangement and operation isfthat the met-al of which the rectangular plate 12 is composed is caused to flow into the opposite depressions'in the edge engaging portions of the dies, so that at the completion of the stroke of the offsetting'dies, the plate 12 will have its longitudinal lines distorted so as to conform to the contour of the olfsetting portions of the dies, and a blank pos- Sessing the several curves desired will be produced in a single operation of the 'offset- .ting press. In the older practice, it was often necessary to cut transversely of the grain of the metal plate .org strip to form the contoured blank, as v'shown in Fig. l, but by the new method of edgewise bending the plate, the grain of theA metal is made to lie parallel to the longitudinal dimensions of the curved blank, whereby the initial strength of the latter is preserved.

An offsetting press equipped with suitable.

dies, will con-stitute an element of the assemblage disclosed in my' said Patent No. 1,397,020. The operation of such offsetting press will be in synchronism with the other elements constituting the assemblage referred to, the yoffsetting press performing its allotted work in a predetermined subdi vision of the time-cycle in which the assemblage effects one complete movement. l It is therefore necessary to the uninterrupted operation of the assemblage and the suc-` cessful practice of my invention, when the offsetting press is operated as an element of the assemblage, that the rectangular metal plates be fed lin regulated timing to the offsetting press in a continuous stream, the

timed offsetting operation upon the rectangular plates being followed by a timed delivery of the curved plates for transmission by suitable conveyor mechanism to the next element of the assemblage designed for further operation upon the said plate. But

when the offsetting press isv operated independently of the assemblage,'the time limitations may be removed.

The side margins of the blank are turned from the plane of the blank in the drawing operation, so as to form the flanges of the bar. Figs. 11 and 12 show the application of my improved process to the conversion' of' a rectangular plate 20 into a curved plate 21, from which a blank for 'a curved and flanged cross barpmay be punched.

In automobile frames constructed from flanged metal plates, it happens that certain portions of the frame parts are subjected to. severe strains, the constructionbeing frequently weakened by the perforation-s in the frame parts through which pass the rivets employed for uniting the frame parts and some of the adjunctive devices' and connections. Heretofore, it has been the practice to apply separate reinforcing plates to the parts of the frame at the points which are subjected to excessive strains, to overcome the inherent liability of the non-reinforced frame to fracture at the weakened points. The application of the reinforcing plate-s under the olderpmethod of constructing automobile frames, involved additional expense for material, as well as for labor in producing and applying such reinforcements.

I propose to obviate the objections of the older practice, and produce in the parts of the automobile frame an integral reinforcement of the metal at the points which are subject to breaking strains. This result I achieve by thickening the cross sectional area of the plate from which the blank is punched, 'so that the side bar or other part will be sufficiently reinforced by the accretion of additional metal at 'the desired points.

To carry out this feature of my invention, I form the offsetting 4dies so that the side clamping faces therefore are separated in an increase degree in certain sections,so as to provide room for expansion of the metal in a plane transverse to that in which the plate lies. At those points in the length lof the side bar where the reinforcement is desired, the edgewise bending portions of the offsetting dies will compress the metal of the late 12 in the offsetting operation, and at t e same time the metal of the plate will flow laterally from the direction of its movement in the bending operation, and completely fill the slight clearance provided in the cut out por- G tions inthe face of the dies. Fig. 17 indicates the normal thickness of the plate 12, and Fig. 18 indicates the same plate after action thereon by the offsetting dies, which in their relative approach act to compress the metal o f the plate, 12 in the desired secg tions, and cause the metal of the said plate V124 to flow in a plane transverse to its width.

duringthe bending operation.

Fig. G'shows an edge. view of a curved side bar blank 13, the ends 22 and 23 of which are shown as having been gra-dually thickcned from the normal gauge of the plate, so as to constitute the plate 13 with integral reinforcements at the sections desired. y

. Fig. 7 is a perspective view of a side bar of an automobile frame, theends 24 and 25 of such' side bar being integrally reinforced in the manner described, so that the side bar will sustain the stra-ins imposed thereon, notwithstanding the fact that the metal has been weakened by perforations for the attachment of the adjunctive devices. Fig. 9 is a cross 'sectional view showing the normal gauge of the stock from which the side bar is formed, and Fi 8 and 10 show by comparison the integra reinforcement, produced as described.

Fig. 13 shows one form of a curved cross bar 26, the arch of which is ordinarily required to be thin in order to provide a clearance for the shaft of the car. Fig. 15 shows the normal gauge of the metal plate from which the cross bar is formed, and Fig. 14 shows in crosssection the manner of inte- CEB only to :be curved to adaptthem to their intended'use. The intermediate step of blanking is not, therefore, an essential element of my new process, by which curved flanged bars are produced from rectangular metal plates which are bent in the direction of their width, and which in a single bending operation have all of the necessary curves imparted thereto.

ln an application filed by me on September 12,1921,Serial No. 500,018, as a division in part of this case, lf have claimed the product resulting from the practice of the invention herein disclosed.

Having thus described my invention, what I claim and desire to secure by Letters Patent of the United States, is:

1. The process of producing curved, flanged bars, which consists in confining a sin le wide metal plate by pressure upon the si es thereof, subjecting the plate to bending pres:

sure applied to the' edges thereof at sepa-v rated points along the Opposite edges of the blank, such separated points at one edge of the plate being staggered with relation to the points on the opposite edge, whereby the metal of the plate will be caused to flow away from the longitudinal center line of the plate, punching a curved blank from the plate, and turning the curved side margins of the blank from the planethereof to form the flanges.

2. rlhe process of making a-curved, flanged y bar, which consists in confining a single wide metal plate by pressure upon the sides thereof, bending the said plate in the direction of its width by pressure applied at separated points tothe opposite edges thereof, such separated points being staggered with relation to the opposite edges of the plate, to

distort the edge lines of such plate, cutting av planes thereof, bending the said plate in the direction of its width by pressure applied to the edges and .at-separated points staggered with relation to each other upon the opposite edges of the plate, to distort the edge lines of such plate, and turning the margins away vfrom the plane of the plate to form the y flanges of the bar.

plate, which consists in clamping a single wide metal plate against disturbance of the side planes thereof, and bending the said-plate in the direction of its width by pressure applied at points alternating on the opposite edges thereof, to cause the metal of the plate to flow away from the longitudinal center line of the plate.

5. The process of converting a rectangular plate into a curved, flanged bar, integrally reinforced in sections of its length, which consists in clamping the plate to preserve the side planes thereof and prevent buckling, bending the plate in the direction of its width by pressure applied at points alternating on the opposite edges thereof and thickening the plate in sections thereof by compression in the bending operation, and turningthe side margins of the plate from the plane thereof to form the flanges of the bar.

6.` The process of converting a rectangular plate into a curved, flanged bar, integrally re inforced in sections of its length, which consists in clamping sections of the plate to preserve the side planes thereof, bending the plate inthe directionofits width by pressure applied at points alternating on the opposite edges thereof and thickening the plate in the unclamped sections thereof by compression of the unclamped `portions in the bending operation, cutting a blank from the said curved plate, and turning the side margins of the plate from the plane thereof to form the flanges of the bar.

7. The process of converting rectangular meta-l plates into curved plates for the manufacture of automobile frame bars, which consists in feeding such rectangular plates in single succession to bending dies, clamping the plate to prevent distortion of the side planes thereof, a plying a bending pressure to the edges of t e plate at separate points alternating on the opposite edges thereof while the sides are clamped, to cause the metal of the plate to flow away from the longitudinal center line of the plate, thickening the plate in sections by compression and withdrawing the curved plates from the bending dies in the order in which they are fed to the dies.

8. The process of making curved flat blanks, which consists in clamping a single, wide metal plate against disturbance of the side planes thereof', `bending the said plate in the direction of its width by pressure applied to the opposite edges thereof at points which are staggered with relation to each other, and cutting a curved blank from the bent plate.

9. The process of makin curved flat blanks which consists in simu taneously applying clamping pressure to the sides of a single, wide metal plate and bending pres sure to the edges thereof, such bending pressure being applied at points which are staggered with relation to each other on the opposite edges of the plate, and cutting a blank of Curved outline from the said bent plate.

10. The process of converting flat plates into plates of curved form, which consists in confining a singley Wide metal plate by presssure upon its'sides to prevent buckling and simultaneously therewith applying bending pressure to the opposite edges thereof.

ln testimony whereof, l have signed my naine atkMilwuukee, this 29th day of March, m 1920.V

C. THEO. OSTERBERG. 

